1. Field of the Invention
The invention relates to a synchronous demodulation circuit for a carrier-modulated television signal, comprising a passive carrier regeneration circuit for obtaining an in-phase and a quadrature reference signal for synchronously demodulating the television signal in an in-phase and a quadrature demodulator, respectively, to outputs of the in-phase and quadrature demodulators being coupled to a first and a second input, respectively, of a combination circuit having an output from which a video signal is obtained.
2. Description of Related Art
A synchronous demodulation circuit of the type described above is known from U.S. Pat. No. 4,157,569, in which the output signal of the in-phase demodulator is directly applied to the combination circuit and the output signal of the quadrature demodulator is applied to the combination circuit via a rectifier circuit. A video signal is then obtained from the output of the combination circuit, which video signal can be used, for example, for obtaining synchronizing signals. This video signal remains usable for this purpose if, for example, due to detuning, a phase difference is produced between the actual and the desired phase of the reference signals. A video signal which is usable for the display in a television image is obtained from the in-phase demodulator.